wittmann



R. A. WITTMANN May 4, 1954 GAS FUELED PILOT ASSEMBLY AND THERMAL CONTROL" ELEMENT Filed Oct. 23, 1950 3 Sheets-Sheet l 3nventor R08ER7' A. WITTMANN a Gttomeg May 4, 1954 R, A. WlTTMANN 2,677,

GAS F UELED PILOT ASSEMBLY AND THERMAL CONTROL ELEMENT Filed Oct. 23, 1950 3 Sheets-Sheet 2 a O O Jnventor Gi /"MW I attorney R. A. WITTMANN 2,677,418

GAS FUEL-ED PILOT ASSEMBLY AND THERMAL CONTROL ELEMENT 3 Sheets-Sheet 5 May 4, 1954 Filed Oct. 23, 1950 Fig 9 Patented May 4, 1954 UNITED STATES P" rsnr GAS FUELED PILOT ASSEMBLYAND THERMAL CONTROL ELEMENT Delaware.

Application October 23, 1950', Ser'iaI'NO. 191,515

1-7 Glaims.

My invention relates to a pilot assembly and more particularly to a compact pilot assembly for use in the oven of a gas stove. 7

One object of my invention is to provide a pilot assembly of aplurality of pilots; an ignition means and a heat responsive element so con structed that the parts have-a permanently fixed relationship to each other.

Another object is to provide an assembly of a plurality of pilots, an ignition means and aheat responsive element in which a pilot flame-must befi'rst' established at a main burner before the gas-which is to'heat the heat responsive element can be ignited.

A. further object ofmy invention is to-provicl e a pilot assembly of a plurality of pilots so ar ranged that each pilot will light all of the other pilots and the main burner and, conversely, the

being adaptedto' be'bolted-to acombusti'on cham ber wall, thereby holding allot the parts in'a fixed position relative to a main burner and permit ting ready. removalof the entire assembly.

A still further object of my invention isto'provide a pilot assembly. of a plurality of pilots with their piping in which the primary air injections and all gasor'ifices will be outside of the'eornbustion chamber.

Another object of my invention is-to provide anassernbly of a plurality of pilotsand a heat responsive element such that the heat applied to the heat responsive element can be supplied from a plurality of sources, thereby distributing the heating gas over an extended surface to obtain the fastest heating possible.

The foregoing and other objects, features and advantages of this invention will be apparent from the following description and from the accompanying drawings 01" a preferred embodiment, it being understood that the detailed description and drawings are merely illustrative of the invention, which is defined in the claims.

In the drawings,

Figure 1 is a diagrammatic representation of a single point ignition system for a gas oven in which a pilot assembly embodying my invention may be used.

Figure 2 is a plan view of one pilot assembly arrangement made in accordance with my invention.

Figure 3 is a front elevation of the pilot assembly.

Figure 4 is a right end view of the pilot assembly.

Figure 5 is a sectional view on the line 5-"-5"of Figure 2;-

2 Figure 6 is a sectional view on the line 6- -6 of Figure 2-. H V Figure? is a sectional view on the line 1 -1 of Figure 2';

Figure 8 is a' plan view of the pilot casting, as seen on the line E- S-of- Figur eB.

Figure 9* is a section of the casting on the line' 99 of Figured:

Figure 10 is a section of the casting on thelir'i'e l0i0 of Figure 8:

Figure-1i is a-sectionof thecastir'ig on the line fold ii; has a Connor knob or handle 3'. when the-- thermostat is turned to the on position, g'as flows-from the manifold-2 through the thermostat intoas'upply'line i, from which it passes through a valve 5 and-a supply tube'fi to afia'sh and acoel' cratingpilot chamber 1- apilot c'a'sting ordis tributor member 8. The casting 8 is' suitably sup portedby a bracket 9, being secured thereto by bolts llll The bracket is secure'd'to a wall I['- of anoven' or combustion-chamberby means offbolts or screws passing through holes- 29 ina flange 22 0f the bracket, in a position to hold the pilotassembly in close proximity to' a main oveii' burner 55.

The gas supply-line l aise leads to another valve l3=and through'it-into a; supply tube M leading to the'm'ai'n oven burner. f5:

Aseparate supply line l6,also-leading from the thermostat i and" being manually controlledthereby, leads to a: chamber H: in thepilot cast-'- ing 8, thischamber being the supply chamber for" a heating or sustaining pilot.

An independent supply line !8,: leading directly from the gas manifold: 2 and not passing through the thermostat, conducts. gas through a third valve i9 and thence througlra; supply tube 2ltinto=- a. chamber 21 in-th'e casting 8,.this chamber supd it outside oft-heoven'walF H.

inspirators ZQ hasa; small, adjustable orifice-mil? plying the gas for the stand-by pilot.

Each of the gas'supply tubes it, I6 and 26 may" be secured tothecasting' 8 in any suitable man; her, as by being threaded into tapped openings in the casting, and each has an orifice 2'2 with: an

adjustable primary air shutterv or adjustment: in"

constantly burning. As indicated in Figure 1; the

line 23' may lee-taken off the line [8, if desired.

A* flash tube 25" is positionedin the" pilot as" sembiy withone open end" abutting against the rear of thepilot casting 8; The flash tube passes Each of the-three through an opening in the flange [2 of the bracket 9 and thus out of the combustion chamber. Itsposition relative to the flange may be partially fixed by means of a ring or collar 26, which is fixed to the flash tube in an eccentric or oblique position in any suitable manner, as by welding or soldering. This collar prevents the flash tube from slipping out through the flange and, due to its oblique position, also prevents rotation of the flash tube. The flash tube is held with its one end in contact with the rear of the pilot casting 8 and with its collar 26 in contact with the flange I2 of the bracket. Its end adjacent to the pilot casting is held firmly between the bracket 9, the gas tubes 6, I6 and and one of the arms 3| of the bracket described hereinafter. If desired, the flash tube may have an aerating slot 27 or other aerating means along its entire length or along part of it. One or more additional sections 28 of flash tubing may be used, as necessary, to extend from the tube up to the top burner pilot 24, these additional sections being held in communication with the tube 25.

In place of the combination of flash tubing and top burner pilot just described, electric ignition may, if desired, be used. Such electric ignition comprises a hot wire adjacent to the ports of the flash pilot and in a position to ignit gas coming from those ports.

A heat responsive or thermal element is held in position over the pilot casting 8 by means of two arms 3| which are part of and extend from the bracket 9. The thermal element, which is generally cylindrical in shape, is supported in slots 32 in the arms 3|. A clip 33 may be used to extend over an extension of the thermal element 39 and thereby to hold it in place, the clip being fixed to the bracket 9, as by means of a sheet metal screw or bolt 34. A small tube leads from the thermal element 38 to a bellows 36 (Fig. 1). This bellows is secured in the same casting as the valves 5, l9 and I3 and they are all mechanically linked together. When the heat responsive element 30, which may be of the mercury bulb type if desired, become heated sufliciently, the expansion of the mercury in the element 30 expands the bellows 36. This action first opens the valve l9, permitting gas to flow through the tube 20 to the stand-by pilot chamber 2|. As the mercury is expanded further, the valve I3 is opened, permitting gas to flow to the main burner I5. About the same time, the valve 5 is closed, shutting off the supply of gas through the tube 6 to the flash pilot chamber 1. The ideal operation is to have all three valves function simultaneously.

As may be seen in Figures 10 and 11, the flash pilot chamber 7 has one or more ports 31 in its rear surface, one of these ports directing into the end of the flash tube 25. (See Fig. 5.) When the oven is to be lighted, the oven thermostat knob 3 is turned on to any temperature setting. Gas is thereby permitted to flow from the gas manifold 2 through the thermostat into the supply line 4. At this time, the heat responsive element 30 is cold and hence the bellows 36 is contracted and the valve 5 is open, the valves I3 and [9 being closed at this time. Gas from the line 4 flows through the valve 5 and the supply tube 6 into the flash pilot chamber I and out through the rear ports 31, as well as through side and front ports. The gas then flows through the flash tubes 25 and 28 up to the top burner pilot 24, where it becomes ignited, the flame flashing back to the pilot casting 8. A series of ports 38 are formed in the side wall of the flash pilot chamber 1, as may be seen in Figures 4, 5 and 10, these ports leading from the vicinity of the ports 31 in the rear of the casting to the front of the casting, in which there is a set of lighting ports 39. The gas in the flash tubes is ignited at the top burner pilot 24 and the flame propagates down through the flash tubes 28 and 25 to ignite the gas coming through the rear ports 31 of the flash pilot chamber. The flame then carries around along the series of ports 38 to the front of the casting, where it ignites the gas coming from the front pilot ports 39. At this time, the pilot is ready to ignite any gas which may be present in the main burner l5, although in normal operation of the oven, there should be no gas in the main burner at this time. One or more accelerating ports 40 may be provided, if desired (as may be seen in Figs. 2, 8, l0 and 11), extending upwardly from the flash pilot chamber 7 through the top surface of the casting 3, in order to furnish a supply of gas to assist in heating the thermal element 3|], or to accelerate its reaching its operating temperature.

At the same time as the control knob 3 permits gas to flow through the line 4, the valve 5 and the supply tube 6 to the flash pilot chamber l, gas is also permitted to flow from the gas manifold 2 through the thermostat l and the supply line l6 into the heating pilot chamber |'l. This heating pilot chamber has at its forward end one or more ports 4| (Figs. 4, 8 and 9). The gas coming through these port 4| will be ignited by the flame coming from the front flash pilot ports 39. A series of heating ports 52 in the top surface of the casting 8 are connected with the heating pilot chamber l1 and extend from the front of the casting toward its rear, these ports being in a position below the thermal element 30. The gas coming through the heating ports 42 is ignited by the flame coming from the ports 4|. The gas coming through the accelerating ports 40, leading from the flash pilot chamber 1, is ignited by the flame coming from the heating ports 42 and assists the heating ports 42 in heating the thermal element 30, so that the heating of the latter is accelerated.

When the mercury or other heat responsive material in the thermal element 3|] is heated partly through its range, the bellows 36 is expanded to open the valve l9, permitting gas to flow through the tube 20 into the stand-by pilot chamber 2 i, from which it passes through one or more ports 43 in the front of the chamber. The gas coming through the ports 43 is ignited by the flames at the ports 39 or II. As the thermal element 30 is heated further and the bellows 36 expands further, the valve [3 is opened, permitting a flow of gas in the main burner 55. The gas in the main burner is then ignited by the flames coming from either the pilot ports 39, 4| or 43.

As the thermal element 39 is heated still more and the bellows 38 expands to the fullest extent, the valve 5 is closed, shutting oil" the supply of gas through the tube 6 to the flash pilot chamber 7. This, of course, extinguishes the flames coming from the ports 38, 33 and 40. The heat of the flames coming from the heating ports 62 is surficient to keep the thermal element 33 fully expanded and it is logical that such heat will not permit overshooting, with consequent fast cooling.

The sequence of operation of the valves l9, l3

55-. andmay be as described'above, or they may all be operated together.

When the control knob 3' is turned to the off position, the supply of gas through the supply line 4, the valve 53 and the supply tube i l to the main burner it is cut off. The supply of gas through the supply line i, the-valve 5 and the supply tube 8 to the fiash pilot chamber 1 has already been shut on by the action of the thermal element 38 and the bellows 36' in closing the valve 5. At this time, gas continues to flow from the gas manifold 2 through the supply line 18, the valve is and the supply tube 28 to the stand-by pilot chamber 2i and through its .ports43, thereby maintaining a flame from those ports. The closing of the thermostat valve by the control knob 3 also shuts off the supply ofgas through the supply line it to the heating pilot chamber 1-1 and thence through its ports 4| and 42. The supply of gas through the upper accelerating ports at of the dash pilot chamber 1- haspreviously been cut on by the action of the thermal element 38. Thus, when the supply is also cut oil from the heating ports 12 of the heating pilot chamber ii, there is no flame heating the thermal consequent contraction of the bellows requires a a few moments, so that gas continues to flow through the supply line !8, the valve 29 and the supply tube to the stand-by pilot chamber 2 I, from whence it oes through the ports 33' and maintains flame from those ports. The purpose of this provision is to permit the cook readily to turn the main burner on again if she changes her mind about needing the burner shortly after having turned it off. It also protects against malfunctioning of the main burner valve 53. When the thermal element 33 has not had suiiicient time to cool and thus the bellows 38 has-not fully contracted, the valve 43 in the main burner line is still open, as is the valve I9 in the stand-by pilot line, the valve 5 in the flash pilot line being at the same time closed. Consequently, ii the thermostat i weresuddenly opened shortly after having been closed, gas would flow through the main burner valve it into the main burner it, but could not flow through the flash pilot valve 5, which is closed. Thus, if there were no flame at stand-by pilot ports 53 a dangerous condition would exist, because a large amount of gas would flow into the combustion chamber before the flash pilot could become operative. This situation p'evented by keeping the gas coming from the stand-by pilot ports 43- for a few moments after the thermostat is turned off, due to the fact that the automatic valveit in the stand-by pilot line remains open.

It will be apparent that I have provided, by my invention, a pilot assembly in which the pilots, the flash tube and the heat responsive element are fixed together in a permanent relationship. The arrangement is such that any one of the pilots will light all of the other pilots and the main burner, and the main burner will also light any of the pilots. The assembly is so made that it can be readily installed or removed from the combustion chamber and can be bolted to the combustion chamber wall, thereby holding all of the parts in a fixed position relative to the mainv burner. The supply tubes. for all of the pilots have all of their primary air injections and all of their gas orifices outside of the combustion r the: main burner.

6" chamber, where they are readily accessible for inspection and adjustment.

The pilot assembly is so designed that a gas pilot flame must first be established adjacent to.

the main burner before the gas which heats the thermal element can-be ignitedito permit a flow of: gas to the main burner. Thiseiiectsa safety factor because no gas can flow to the main burner unless there is a pilot flame burning.

factor, eliminating the danger of explosion.

I claim: I

1-. In a gas burner assembly including a main.

burner, a pilot" burner and a heatresponsive element; a pilotassembly comprisingv a distributor memberhaving a plurality of. separatechamhers-therein, a gassup'ply tube leading to each of said chambers and a hash tube extendin'gup wardly from the vicinity of a first one of said chambers, atleast one port in said first chamber coactin with said flash tube, a series or portsin.

said first chamber extending from the vicinity,

of said flash tube to a position in proximity to the main-burner, a second one of said chambers having aseries of: ports therein extending from a position adjacent to said main burner to. a position near the heat responsive element, and a third one of said chambers having atv least one port adjacent to said main burner.

2. In a gas burner assembly including a main burner, a pilot: burner and a heat responsive element, a pilot assembly comprising a distributor member having a plurality of separate chambers. therein, a gas supply tube leading to each oi aid,

chambers and a flash tube extending upwardly from the vicinity of'a first one of said chambers,-

at least one port in said first chamber coasting with said fiash tube, a series of ports in said first-- chamber extending from the vicinity of said flash.

-- tube to a position in proximity to the mainburner, a-second one of said chambers havingia; series of portstherein extending from a position adjacent to said main burner to a position near the heat responsive element, said first chamber also having ports adjacent to said heat responsive.

element, and a third one of said chambershaving at leastone port adjacent to saidmain burner.

3. In a gas burner assembly including a main burner, a pilot'- burner and a heat responsive element, a pilotassembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers and a flash tube extending upwardly from the vicinity of a first one ofsaid chambers, at least one port in said first chamber coacting with said flash tube, a series of ports in said first chamberextending from the vicinity of saidiiash tube t'o a positionin-proximity to the main burner, a second one of saidtchambers having a series of ports therein extending from a position adjacent to: said main-burner to a position near the heat responsive element, and a'third one of said chambers having at least one port adjacent to said main burner, at least one port in each chamber being so located as to light the other ports and the main burner.

4. In a gas burner assembly including a main burnena. pilot burner and a heat responsive element, a pilot assembly comprising adistributor member having a plurality of separate chambers to said main burner to a position near the heat responsive element, said first chamber also having ports adjacent to said heat responsive element, and a third one of said chambers having at least 7 one port adjacent to said main burner, at least one port in each chamber being so located as to light the other ports and the main burner.

5. In a gas burner assembly including a main burner, a pilot burner and a heat responsive element, a pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers and a flash tube extending upwardly from the vicinity of a first one of said chambers, at least one port in said first chamber coacting with said flash tube, a series of ports in said first chamber extending from the vicinity of said flash tube to a position in proximity to the main burner, a second one of said chambers having a series of ports therein extending from a position adjacent to said main burner to a position near the heat responsive element, and a third one of said chambers having at least one port adjacent to said main burner, at least one port in each chamber being so located as to be lighted by the main burner.

6. In a gas burner assembly including a main burner, a pilot burner and a heat responsive element, a pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers and a flash tube extending upwardly from the vicinity of a first one of said chambers, at least one port in said first chamber coacting with said flash tube, a series of ports in said first chamber extending from the vicinity of said flash tube to a position in proximity to the main burner, a second one of said chambers having a series of ports therein extending from a position adjacent to said main burner to a position near the heat responsive element, said first chamber also having ports adjacent to said heat responsive element, and a third one of said chambers having at least one port adjacent to said main burner, at least one port in each chamber being so located as to be lighted by the main burner.

'7. In a gas burner assembly including a main burner, a pilot burner and a heat responsive element, a pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, an ignition means adjacent to a first one of said chambers, a series of ports in said first chamber extending from the vicinity of said ignition means to a position in proximity to the main burner, a second one of said chambers having a series of ports therein extending from a position adjacent to said main burner to a position near the heat responsive element, said ignition means establishing a flame first at the ports adjacent to itself, the flame thence propagating along the series of ports of the first chamber from the vicinity of said ignition means to a position in proximity to the main burner and thence to the ports of said second chamber from those ports adjacent to the main burner to the ports near the heat responsive element.

8. In a gas burner assembly including a main burner, a pilot burner and a heat responsive element, a pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers and a flash tube extending upwardly from the vicinity of a first one of said chambers, at least one port in said first chamber coacting with said flash tube, a series of ports in said first chamber extending from the vicinity of said flash tube to a position in proximity to the main burner, a second one of said chambers having a series of ports therein extending from a position adjacent to said main burner to a position near the heat responsive element, said flash tube establishing a flame first at the ports adjacent to itself, the flame thence propagating along the series of ports of the first chamber from the vicinity of said flash tube to a position in proximity to the main burner and thence to the ports of said second chamber from those ports adjacent to the main burner to the ports near the heat responsive element.

9. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, and a bracket for supporting said distributor member and said tubes in fixed relationship to each other.

10. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a fiash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, a heat responsive element, and a bracket for supporting said distributor member, said tubes and said heat responsive element in fixed relationship to each other.

11. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, a heat responsive element, and a bracket for supporting said distributor member, said tubes and said heat responsive element in fixed relationship to each other, whereby said pilott assembly can be removed and replaced as a um 12. A gas pilot assembly comprising a distributor member having a lurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, and a bracket for supporting said distributor member and said tubes in an oven compartment of a stove and in fixed relationship to each other.

13. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, and a bracket for supporting said distributor member and said tubes in an oven compartment of a stove and in fixed relationship to each other, with the primary air orifices and all gas orifices of said gas supply tubes located outside of said oven compartment.

14. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, a heat responsive element, and a bracket for supporting said distributor member, said tubes and said heat responsive element in an oven compartment of a stove and in fixed relationship to each other.

15. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, a heat responsive element, and a bracket for supporting said distributor member, said tubes and said heat responsive element in an oven compartment of a stove and in fixed relationship to each other, with the primary air orifices and all gas orifices of said gas supply tubes located outside of said oven compartment.

16. A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers, an ignition means adjacent to a first one of said chambers, a series of ports in said first chamber extending from the vicinity of said ignition means to a position in proximity to a main burner and a series of ports in a plurality of said separate chambers forming a series adapted to extend from a position adjacent to said main burner to a position near a heat responsive element, whereby a flame is established adjacent to the main burner before a flame under the heat responsive element can be established.

17 A gas pilot assembly comprising a distributor member having a plurality of separate chambers therein, a gas supply tube leading to each of said chambers and a flash tube adapted to extend from a pilot flame to the vicinity of a first one of said chambers, at least one port in said first chamber coasting with said flash tube, a series of ports in said first chamber adapted to extend from the vicinity of said flash tube to a position in proximity to a main burner and a series of ports in a plurality of said separate chambers forming a series adapted to extend from a position adjacent to said main burner to a position near a heat responsive element, whereby a flame is established adjacent to the main burner before a flame under the heat responsive element can be established.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,360,607 Kaufiman Oct. 17, 1944 2,450,680 Mueller Oct. 5, 1948 2,506,403 Witzel May 2, 1950 2,511,208 Hornung June 13, 1950 

